haha you know before i even starting reading this thread, the idea of mimic monsters popped into my head. initially was thinking some minerals might have some sort of mineral eating monster inside when you cracked it open, but thats silly. and those rooms are usually supposed to be safe. so scratch that.
however I love your level ideas and the hazards. like the idea of better rewards being available if you can clear the level fast (the tradeoff also being that you might skip some enemies or boxes in an effort to be fast, so its not necessarily more lucrative!). not so sure about the competitive team one, but the others I definitely like.
I really enjoyed reading this thread, until I got to the last line. You proposed some very interesting and ingenious ideas that were surprisingly fleshed out. I was glad to see someone actually thinking about placement of triggers and buttons in relation to the stage type. Some of the obstacles/traps were also interesting, but reading the last line made me fume. Mimics? The most overused MMO(RPG) element out there? Really? I am so tired of them! All they do is increase general anxiety. Plus, since you can't actually shoot bushes, you'd HAVE to get close enough to hit them. The one thing I COULD see as a potential benefit would be people using actual guns for once, instead of just dual swords. Other than that, I cringe at the idea of mimics...omnomnomRAGE!
But seriously, a treasure hunting level would be cool...you'd have to explain the level type before the first button, and then wait to start the time until the first team button is pressed. That way everyone KNOWS it's a race and some noob doesn't just go through it at snail pace while you all wait at the button...